1. Field of the Invention
The present invention relates to a vehicular steering apparatus.
2. Description of Related Art
A vehicular steering apparatus featuring a shock absorbing function includes, for example, a type wherein during a collision, a steering column is adapted to be bodily moved toward a front side of a vehicle body along a longitudinal direction of the steering column.
On the other hand, a steering apparatus permitting a positional adjustment of a steering wheel with respect to the longitudinal direction of the steering column includes a type wherein the whole body of the steering column to be adjusted is moved relative to the vehicle body along the longitudinal direction of the steering column.
The steering column assemblies of the former and latter types normally have an arrangement wherein a fixing bracket secured to the vehicle body has a pair of side plates, whereas a column bracket secured to the steering column is disposed between the pair of side plates of the fixing bracket. The side plates of the column bracket are each formed with a slot extended along the longitudinal direction of the steering column. A support shaft inserted through the slots is fixed to the fixing bracket. Thus, the support shaft is allowed to move along the slot when the steering column is moved relative to the vehicle body.
In order to permit the movement of the support shaft along the slot, however, a predetermined clearance need be provided between an outer periphery of the support shaft and a circumferential edge of the slot. This may result in an unwanted play or poor fit of the steering column.
Therefore, it is a common practice to fit a resin collar for poor-fit elimination on the periphery of the support shaft so that an outer periphery of the resin collar is fitted in the slot. Unfortunately, an influence of varied dimensional tolerances of individual components may lead to a problem that the resin collar is strongly compressed between the circumferential edge of the slot and the outer periphery of the support shaft, or conversely that a clearance is produced between the outer periphery of the collar and the circumferential edge of the slot, resulting in the play of the steering column.
The former problem includes an increased resistance to the movement of the support shaft along the slot. This may lead to a failure of ensuring a required amount of shock-absorbing stroke because the steering column being moved to absorb an impact energy may be arrested at some midpoint of the shock-absorbing stroke. Furthermore, an increased manipulation force may be required for adjusting the position of the steering wheel with respect to the longitudinal direction of the steering column.
In view of the foregoing, it is an object of the invention to provide a vehicular steering apparatus adapted to prevent the play of the steering column and to ensure a stable resistance to the relative movement between the slot and the support shaft.